Oregon agency extends fight against Japanese beetles

SALEM — The Oregon Department of Agriculture plans to expand its campaign against crop-eating Japanese beetles.

The agency has proposed applying a granular insecticide over 1,900 acres around the Cedar Mill and Bethany neighborhoods in unincorporated Washington County. Two public meetings have been scheduled for February, the Capital Press reported .

In 2016, the department detected hundreds of beetles in Cedar Mill and Bethany, adjacent to northwest Portland.

The confirmation of an infestation prompted a five-year project to wipe out the beetles, and roughly 1,000 acres were treated last spring.

Still, the department detected more than 23,000 beetles later that summer, including 750 outside the treatment zone.

“We were anticipating thousands of beetles, not tens of thousands of beetles,” said Clint Burfitt, insect pest program manager for the department.

Burfitt does not know where the beetles came from, but suspects potted plants brought in by a homeowner. He said beetles have historically arrived from other states through Portland International Airport.

The Japanese beetle feeds on a variety of plants and crops, including grapes, berries and orchard fruit. The agency estimates the beetles would cost Oregon agriculture $43 million per year if they became established and dispersed throughout the state.

Increased monitoring statewide led to the discovery of 11 Japanese beetles in Douglas County in the southwestern part of the state. Another 11 beetles were found at the Portland airport and five at Swan Island in Portland.

In addition to nearly doubling the treatment area in Washington County, the department wants to treat 150 acres at the Portland airport and 34 acres in Douglas County. Traps, not insecticide, are planned at Swan Island.

It will take about six weeks to apply the product known as Acelepryn on all grass and ornamental plant beds in the treatment area. Applications are free, but property owners must give permission for the Agriculture Department to enter their properties.